I would understand if it was taken, but it seems like the problem was that it CONTAINED a taken username? What is the deal with that? So what if "spac" is taken I don't want to be spac I want to be SpaceCase -3-
You can customize a username after you've registered. It will be used as your display name on the site. Several of us including myself have done it.
Not taken, it's blocked as part of what, seems to me, a block that bans variations of 'spaz' and 'spack'